Nonperturbative quark-antiquark interactions in mesonic form factors

14 Aug 2020  ·  Shuryak Edward, Zahed Ismail ·

The existing theory of hard exclusive QCD processes is based on two assumptions: (i) $factorization$ into a $hard$ $block$ times light front amplitudes (or wave functions); (ii) use of perturbative gluon exchanges within the hard block. However, unlike DIS and jet physics, the characteristic momentum transfer $Q$ involved in the factorized block is not large enough for this theory to be phenomenologically successful... In this work, we revisit the latter assumption (ii), by explicitly calculating the $instanton$-$induced$ contributions to the hard block, and show that they contribute substantially to the vector and scalar form factors of the pseudoscalar and vector mesons, over a wide range of momentum transfer. read more

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High Energy Physics - Phenomenology High Energy Physics - Lattice High Energy Physics - Theory Nuclear Theory